Mowing apparatus

ABSTRACT

A mowing apparatus adapted for mounted disposition upon a vehicle comprising a mounting arm, and first and second cutter blade-carrying arms presented in generally side-by-side relationship with resilient means for urging said arms toward each other; there being blade guards carried on said first and second arms. Said resilient means are yieldable upon impact of said guards with an upright so as to maintain said guards in contact with the upright while moving relatively therepast to present said blades for trimming grass and the like adjacent to said upright.

United States Patent 1191 Thompson, Jr. 51 Feb. 13, 1973 [5 1 MOWINGAPPARATUS 3,183,651 5/1965 Hoefler ..56/10.4 Inventor: Philip Thompson J16 Sunset 2,673,366 3/1954 Johnson ..56/10.4 UX

Trail Austm 78745 Primary ExaminerLouis G. Mancene [22] Filed: July 19,1971 Assistant ExaminerJ. A. Oliff 1 pp No: 163,598 Altorney-Ralph W.Kalish [57] ABSTRACT [52] U.S. Cl. ...5566/ll0 74,5566/ll6l.99, 56/153,A mowing apparatus adapted for mounted disposition l 56/3202 upon avehicle comprising a mounting arm, and first hit. Ci. and Second cutterblade carrying arms presented i [58] new of Search generallyside-by-side relationship with resilient means 56/155 320113202 forurging said arms toward each other; there being blade guards carried onsaid first and second arms. [56] References C'ted Said resilient meansare yieldable upon impact of said UNITED STATES PATENTS guards with anupright so as to maintain said guards in contact with the upright whilemoving relatively 3,261,150 7/1966 Fitzgerald, Sr. ..56/l0.4 therepastto present said blades for trimming grass and 3,599,403 8/1971 'Gantz A1 ..56/10.4 the like adjacent to aid upright 3,l 15,739 12/1963 Thoen etal.. .56/l0.4 UX 3,397,521 8/1968 Danuser 56/104 X 8 Claims, 17 DrawingFigures Pmmmrza 13 1915 3,715,872 SHEET 1 BF 8 FIG I INVENTOR PHILIPTHOMPSON, JR.

ATTORNEY PATENTEDFEBIS I973 3,715,872 SHEET 2 OF 8 wunuunnn, "nun"... l;

IIIIIIIIIIIII INVENTOR PHILIP THOMPSON, JR.

BY Q A v. K wi AT TORNEY PATENTEDFEB 13 I975 SHEEI 3 OF 8 INVENTORPHILIP THOMPSON, JR.

ATTORNEY PATENTEUFEB13 I975 SHEET t 0F 8 INVENTOR PHILIP THOMPSON, JR.

-fiA Y- 61 41 ATTORNEY PATENTEDFEB 13 I975 INVENTOR PHILIP THOMPSON, JR.

ATTORNEY PATENTEDFEB13 191a SHEET 8 OF 8 INVENTOR PHILIP THOMPSON, JR.

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ATTORNEY PATENTEDFEB 1 3 1973 3,715,872 SHEET 7 or a INVENTOR PHILIPTHOMPSON, JR.

BY @Aw/dw ATTORNEY PATENTEDFEB13 ms 3.715.872 SHEET 8 [IF 8 FIG. l6

PHILIP THOMPSON. JR.

BY H N W' ATTORNEY MOWING APPARATUS BACKGROUND AND SUMMARY OF THEINVENTION This invention relates'in general to mowing equipment and,more particularly, to a mower which is suited for mowing or trimmingaround posts, trees, poles, and the like.

It is a primary object of the present invention to provide mowingapparatus which is particularly adapted for efficient mowing of grassand weeds about uprights, such as posts, trees, and the like, as well asunder guard rails along the side of roads, thereby obviating the resortto manual effort for close trimming action.

It is another object of the present invention to provide a mowingapparatus of the type stated which is readily adaptable for mountingupon various types of vehicles whether they be motor driven or pushed byhand.

It is a further object of the present invention to provide a mowingapparatus of the type stated which may be most economically constructed,having marked simplicity of components fabricated of durable materialsso as to render the apparatus extremely reliable and resistant tobreakdown in usage.

It is another object of the present invention to provide a mowingapparatus of the type stated having cooperating cutters so mounted as toeffectively cut grass and the like immediately adjacent a post or tree,which components are so conceived as to function in an automatic manner.

It is another object of the present invention to provide a mowingapparatus of the type stated wherein the cooperating cutting elementsmay be controlled with respect to each other through various, optionallyselectable means.

It is a still further object of the present invention to provide amowing apparatus of the type stated which is amenable to volume inproduction; the operation of which does not require developed skill onthe part of the user; the use of which conduces to substantial economiesand labor such as of the type currently being utilized in conjunctionwith maintenance of areas bordering highways, parks, golf courses, andthe like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a mowingapparatus constructed in accordance with and embodying the presentinvention illustrating the same as supported upon a farm tractor.

FIG. 2 is an elevational view taken on the line 22 of FIG. 1.

FIG. 3 is an elevational view taken on the line 3-3 of FIG. 1.

FIG. 4 is a vertical transverse sectional view taken on the line 44ofFIG. 1.

FIG. 5 is an elevational view taken on the line 55 of FIG. 1.

FIG. 6 is a plan view taken on the line 6-6 of FIG. 5.

FIGS. 7, 8, and 9 are plan views illustrating successive relativepositions of the mowing apparatus during trimming action.

FIG. is a plan view of another form of mowing apparatus constructed inaccordance with and embodying the present invention.

FIG. 11 is an elevational view taken on the line 11- 1 1 of FIG. 10.

FIG. 12 is a vertical transverse sectional view taken on the line l2-12ofFIG. 11.

FIGS. 13, 14, and 15 are plan views which illustrate successivepositions of the mowing apparatus during trimming action.

FIG. 16 is a top plan view of a further form of a mowing apparatusconstructed in accordance with and em bodying the present invention,illustrating same as mounted upon a manually directed vehicle.

FIG. 17 is a side elevational view of the mowing apparatus illustratedin FIG. 16, as taken along line 17 17 of FIG. 16.

DESCRIPTION OF THE PRACTICAL EMBODIMENTS Referring now by referencecharacters to the drawings which illustrate practical embodiments of thepresent invention, A generally designates a mowing apparatus assupported upon a conventional motor vehicle such as a farm tractor B.Mower A is suitably suspended from the body of tractor B, for example,as by support arms 1,1 which extended rearwardly of tractor B and areadapted for vertical reciprocal movement; said arms 1,1 at their lowerrearward ends being engaged to a beam 2 constructed preferably ofgeneral channel stock and with its longitudinal axis normal to the majoraxis of tractor B. Said beam 2, serving as a boom, is connected adjacentits ends by swing arms 3,3 to an elongated mounting arm 4 which ispreferably of tubular stock having a box cross section and being ofrelatively greater length than said beam 2 so as to project at one end,as at 4, beyond the proximate end of beam 2 and laterally outwardly ofthe adjacent rearward wheel w of said tractor B. By reason of themounting of swing arms 3,3 as by bolts 5,6 the same are adapted forrocking to allow of axial shiftable movement of mounting arm 4 forpurposes presently appearing. However, said mounting arm 4 is urged intomaximum laterally extended condition (as shown in FIG. 1) through thebias of an extension coil spring 7 secured at one end to the proximateflange of beam 2 and at its other end to a link 8 rockably secured tothe lower ends of bolts 5,6 which engage swing arm 3'; said latter beinglocated upwardly of link 8. Mounting arm 4, on its forward faceproximate the extremity of its projecting portion carries an extension 9which is received within the bifurcated end, as at 10, of an inner arm11 for hinge formation; there being a hinge pin 12 which progressesthrough aligned openings in the said bifurcations and in extension 9whereby inner arm 11 is swingable within a horizontal plane about theaxis of binge pin 12 for movement toward and away from tractor B. At itsend remote from said hinge pin 12 inner arm 11 is rigid with avertically presented hub 13 which incorporates bearing assemblies 14,15for accommodating a driven shaft 16 which projects below bearing 15 andcarries on its lower end a rotary cutter blade 17 for rotation with saidshaft 16. Suitably mounted upon hub 13 beneath arm 11 and upwardly ofbearing assembly 15 is a collar 18 having bearing assemblies 19, 20 forrendering same freely rotatable about hub 13; said collar 18 being fixedas by welding to the top circular plate 21 of a cylindrical blade guard22 which incorporates a skirt'23 depending from plate 21 and terminatingimmediately upwardly of cutter blade 17 to prevent interference with theeffective operation of the latter but provide adequate protection.Provided within skirt 23 spacedly thereabout is a plurality of enlargedapertures 24 for discharge therethrough of grass or the like severed bycutter 17.

Inner arm 11 will normally project in a direction parallel to thedirection of'travel of vehicle B, that is, axially parallel with thelongitudinal axis of tractor B as shown in FIG. 1. On the side of arm 11confronting vehicle B and proximate the connection to hinge pin 12 is abracket 25 to which is engaged one end of a piston 26 of a fluid,although preferably hydraulic, assembly 27 comprising a cylinder 28within which said piston 26 is axially reciprocally slidable. Cylinder28 is pivotally mounted at its piston-remote end to a bracket 29extending forwardly from the adjacent forward face of mounting arm 4,and is suitably connected by a flexible conduit 30 to a fluid pump andreservoir unit, indicated generally 31, being supported upon a framestructure 32 presented upwardly of beam 2 and carried upon vehicle B.Thus, upon the application of fluid to cylinder 28 piston 26 will beurged into extended condition for biasing inner arm 11 in outwardlyswung condition that is, away from vehicle B.

Mounting arm 4 at its projected extremity is received within thebifurcated end, as at 33, of an outer arm 34 for developing a hingejoint therewith by means of a hinge pin 35 extending through registeringopenings in the bifurcations of arm 34 and mounting arm 4 (FIG. 3), thusouter arm 34 is swingable within a horizontal plane by means of thevertical axial rotation developed by hinge pin 35. Said inner arm 11 andouter arm 34 are co-planar with hinge pin 35 being located slightlyrearwardly and laterally of binge pin 12 so that, perforce, arm 34 willbe fundamentally slightly to the rear and laterally outwardly of innerarm 11. At its forward, or hinge pin remote end, arm 34 carries a hub13' having bearing assemblies (not shown) for accommodating a drivenshaft 16' which on its lower end mounts a cutter blade 17; there being acollar 18 rotatable about hub 13 and fixed to a cylindrical blade guard22'. All of said last mentioned components being of the same characterand for the same purpose as the corresponding components above describedwith respect to inner arm 11. On. its laterally outward face, arm 34,proximate hinge pin 35 is a rigidly affixed bracket 36 with a rearwardtapered end extremity 36 to which is pivotally engaged thenormally outerend of a piston 37 of a fluid, preferably hydraulic, assembly 38including a cylinder 39 which latter is suitably connected, as by aflexible conduit 40, to fluid reservoir unit 31. Said fluid assembly 38is of relatively greater capacity than fluid assembly 27 with piston 37being of relatively greater length and diameter, and capable of agreater stroke. Therefore, a predetermined differential is effected sothat the bias of outer arm 34 in a direction toward vehicle B underinfluence of fluid assembly 38 is substantially greater than the bias ofouter arm 11 outwardly, away from vehicle B. The fluid assemblies 38,27thus coact to urge arms 34 and 11 together with their supported cutters17', 17 and guards 22,22 toward each other; whereby guards 22,22 willnormally be in substantial line contact on their confronting skirtportions.

It will be further seen that by reason of the disposition of arm 34 withrespect to arm 11 guard 22' will be slightly to the rear of guard 22 andoutwardly thereof.

Driven shafts 16,16 may be rotated by suitable means for causing cutterblades 17,17 to rotate for mowing purposes. However, in the present formof the invention such shafts 16,16 are operated from a fluid motor 41carried upon a bracket 42 fixed to, and extending rearwardly from,mounting arm 4 in its central portion. Said motor 41 is appropriatelyconnected by flexible conduits 43,43 to reservoir unit 31 and isprovided with a main shaft 44 carrying a double groove sheave 45 forengaging the inner end portions of flexible transmission belts 46,47;the outer end of the former being trained about a pulley 48 carried onthe upper end of hinge pin 12 and the latter in its outer portion beingtrained about a pulley 49 mounted upon the upper end of binge pin 35 forrotation therewith. Each of said pulleys 48,49 also engage an endlessbelt 50,51, respectively, for engaging pulleys 52,52 mounted on theupper end of shafts 16,16, respectively. To assure of effective motiontransmission for motor 41 to driven shaft 16, a tensioning device 53 isfixed on mounting arm 4 for engaging belt 46 while a takeup wheel 54 isdisposed upon mounting arm 11 immediately proximate pulley 48. Atensioning wheel 55 for engaging belt 51 is carried on the end of an arm56 swingably mounted at its inner end upon the upper surface of outerarm 34. Accordingly, upon operation of motor 41 driven shafts 16,16 willbe caused to rotate for operating blades 17,17. Fixed on the inner faceof arm 34, beneath belt 51 is a guide rail 57, the forward portion ofwhich overlies an edge of top plate 21' and the rearward portion ofwhich inclines inwardly toward the plane of the side face of arm 34.

The operation of mowing apparatus A may be more readily understood byreference to FIGS. 7, 8, and 9, which illustrate the relativedisposition of arms 11, 34 during the trimming of grass or the likeimmediately about an upright such as a tree, post, and the like,indicated generally at P. The operator of vehicle B will so direct thelatter as to cause the particular upright P which is to be trimmed, tobe contacted by guard 22 in its forward outer quadrant as at a so thatthe associated cutter blade 17 is presented for trimming the relatedarea about said upright P. As vehicle B moves forwardly upright P willbe caused to strike guard 22' in its forward inner quadrant as at b andwill by such operation effect a relatively rearwardly directed forceagainst guard 22 which will cause arm 34 to be rearwardly swung aboutits hinge pin 35 but by reason of the urging of fluid cylinder of anassembly'38 said guard 22' will maintain contact with upright P so thatthe related cutter blade 17' is effecting a trimming in the adjacentzone. The continued travel of vehicle B will effect a continued relativerearward swinging of arm 34 with requisite parting of the same from arm11 so as to allow upright P to relatively move therebetween (see FIG.8). Such action will exert a contracting of piston 37, against the fluidpressure so that requisite yieldability of arm 34 is assured. However,by reason of the retraction action of piston 37 a commensurate extendingaction is accorded piston 26 of fluid assembly 27 thereby causing arm 11to be swung laterally outwardly about its pivot axis establishedby-pivot pin 12 so that the related guard 22 is moving about upright Pfor continuing the trimming action by the respective cutter blade 17while the other cutter blade 17' is operating against an opposed areaadjacent upright P.

As the forward travel of vehicle B continues further rearward swingingof outer arm 34 is brought about until the same extends substantiallyrearwardly (see FIG. 9) but with engagement being maintained withupright P so that the trimming action is completed and with the relatedpiston 37 being caused to become substantially fully retracted. Piston26 of fluid assembly 27 is commensurately fully extended causing innerarm 11 to be swung into its maximum outer limit of movement. The uniquerelationship of arms 11,34 assures that trimming is effected around theentire circumference of upright P. Thus, cutter blade 17 associated withinner arm 11 will operate, as it were, against the portion of upright Pconfronting vehicle B through an arc of substantially 180 and then asindicated in FIG. 8 will also effect cutting through the outer remotequadrant of said upright P. Cooperatively cutter blade 17 will operateagainst the outer proximate quadrant of upright P and thence also aboutthe portion of said upright P facing tractor B (see FIG. 9) so that noareas adjacent upright P are left unattended.

Manifestly, cutter blade 17, together with its associated guard 22 willlose contact with upright P before blade 17' and its guard 22. Thelatter after having cleared upright P will be restored to initialposition through fluid acting upon piston 37 and with commensurateretraction of piston 26 by reason of inward swinging of arm 11 underinfluence of said piston 37; it being recognized that piston 26 is notindependently retractable but functions in complementary correspondenceto the action of piston 37.

From the drawings it will be observed that guard rail 57 serves toprevent untoward damaging contact between upright P and arm 34 withassociated components; said guard rail however does not interfere withthe requisite cutting action.

From the foregoing it will thus be seen that arms 34 and 11 are under adifferential bias which urges same together but with the bias beingsufficiently yieldable so that the arms with their associated bladeguards 22,22 may act as cam followers with relationship to the uprightto be trimmed which latter acts in the fashion of a cam. Thus, thecutters are in effect urged immediately against the upright P and are sorelatively arranged as to jointly circumscribe the same for fulltrimming action. Once the upright P has been passed and the camminginfluence is thus lost arms 11 and 34 with their blade guards 22,22 arerestored to initial position under influence of the differential bias.

Swing arms 3,3 provide a most important safety function in that the samepermit of a swinging of mounting arm 4 with the elements carried thereonin the event pistons 37,26 have reached a limit of mutual yieldability.Thus, if through some misalignment as through inadvertent operator errorupright P were to be presented into contact with the hinge connectionsof arms 11,34 the relative force would cause mounting arm 4 to shift,against the bias of spring 7 so as to prevent damage to the apparatus.Thus the swingable mounting of mounting arm 4 provides an emergencyprotection in the event the strokes of the pistons of the hydraulicassemblies have reached their respective limits.

From the foregoing itis thus evident that mowing apparatus A isextremely effective for trimming about posts, trees, and the like withsuch trimming action being automatic. The disposition of such apparatusupon tractor B is set forth for purposes of illustration for it isobvious that the unit may function equally effectively with other typesof vehicles.

Turning now to FIG. 10, A generally designates a mowing apparatusconstructed in accordance with the present invention but differing fromapparatus A hereinabove described in subjecting the cooperating arms toa resilient but yieldable force other than as developed through fluidassemblies. Apparatus A incorporates a mounting arm 60 which is carriedupon a beam 61 by means of spaced apart swing arms 62,62 and with saidmounting arm 60 having the same relationship to beam 61 as mounting arm4 with respect to beam 2 described hereinabove in conjunction withApparatus A. Thus, arm 60 will project at one of its end portions, as at60', beyond the proximate end of beam 61. In its outer end arm 60 mountsa shaft 63, axially normal to the longitudinal axis of arm 60 andprojecting thereabove for purposes presently to be shown. Disposed uponshaft 63 in its lower portion, immediately above arm 60 for swingabilitythereabove, are the inner ends of inner and outer arms 64,65; saidlatter overlying the former and both being formed preferably of flatstock. Each of said arms, 64,65 at their outer end extremities, and ontheir under surfaces, fixedly carry brackets 66 for supporting wheels67, said latter being freely swingable about their mounting. At pointsslightly beyond their intermediate zone, each arm 64,65 supports anupstanding hub 68 for journaling therein of a driven shaft 69 which, attheir lower ends, downwardly of the related arms 64,65, carry cutterblades 70. Rotatably mounted upon each hub 68 is a collar 71 rigid withrelated cylindrical cutter guards 72,72 which are in all respectsidentical with cutter guards 22,22 hereinabove described in conjunctionwith apparatus A.

Also carried upon shaft 63, immediately above arm 65, is a relativelylarge diameter sheave 73 being freely rotatable about shaft 63 forguiding a section of a tension cable 74, one end of which is anchored,as by a pin 75, upon the upper face of arm proximate sheave 73 and theother end of which is secured in one corner portion of a triangularbracket 76 which is pivotally mounted in its apex zone, as at 77, uponthe forward end portion of a cross arm 78; which latter progressesrearwardly across the upper face of mounting arm 60 and is pivotallyengaged thereto, as at 79, for swinging within a a horizontal planeparallel to the plane of arm 60. Cross arm 78 projects a short distancebeyond the sideedge of mounting arm 60 remote from the connection tobracket 76 and in its extended rear portion, as at 80, is apertured forengaging the hooked end of an extension coil spring 81, the axis ofwhich is substantially parallel to the longitudinal axis of mounting arm60 and the opposite or outer end of which is connected by an adjustmentscrew 82 to a bracket 83 rigid upon the rearward face of arm 60 adjacentits outer end. Thus, said spring 81 urges the rearward end of cross armoutwardly, that is, toward the end 60' of arm 60.

The remaining corner of bracket 76 receives one end of a companiontension cable 84 which progresses outwardly toward the outer end ofmounting arm 60 and is trained about a pulley 85 carried upon the upperface of arm 65 proximate anchor pin 75; with the other end of said cable84 being fixed upon a pin 86 mounted on arm 64 (FIG. Thus, by reason ofthe cables 74,84, cross arm 78, and spring 81, and arms 64,65 are nor- 1mally urged into such relationship that their respective blade guards72,72 are in substantially side-by-side contacting condition. In effect,cable 74 will customarily cause a pulling upon arm 65 for directing ittoward arm 64, while cable 84 will exert a pushing effect upon arm 64for influencing same in a direction toward arm 65.

Shaft 69 may be rotated through various means for assuring of requisiteoperation of cutter blades 70. For purposes of illustration, the sameare rotated by means of a suitable take-off (not shown) from a powersource, such as provided by a tractor or the like, and including a shaft87 engaged within a gear box 88 carried upon arm 60; which box includesan output shaft 89 extending thereabove and mounting a drive wheel 90about which is trained one end of a flexible transmission belt 91, theopposite end of which extends about the lower groove 92 of a preferablythree-groove sheave 94 carried upon the upper end of shaft 63; therebeing suitable roller bearings 95 for such mounting (FIG. 12). Sheave 94embodies intermediate and upper grooves 96,97 for receiving the endportions of belts 98,99, respectively, for connecting said sheave 94with pulleys 100 carried upon the upper ends of each driven shaft 69.Thus, upon suitable energization of the related power source, shafts 69will be caused to rotate for grass cutting action.

Presented for detent purposes, is a plate 101 mounted as by bolts 102upon the upper face of arm 60 so as to present a side margin, as at 103,in normal axially parallel relationship to arm 64 and being presentedinwardly thereof, that is, toward the left hand side of FIG. 10. Fixedon said inner margin 103 proximate the forward end thereof, andprojecting therefrom, is a spring 104 for shock-absorbing engagementwith arm 64 in the event of the swinging of the same thereagainst.

Turning now to FIGS. 13, 14 and 15, the operation of apparatus A willnow be described. It will be observed that arms 64,65 and their relatedblade guards 72,72 are thus positioned upon travel of the supportingvehicle for trimming about a fence, post, or the like, indicated at P.Apparatus A is so presented to upright P as to cause the latter to beinitially contacted on the side face of blade guard 72 in its outer,forward quadrant a. Just as in the manner discussed hereinabove withrespect to mowing apparatus A upright P will act as a cam with respectto blade guards 72,72 so that the related arm 64,65 will be caused, ascam followers, to be swung so as to present the related bladesimmediately adjacent upright P for trimming thereabove. The appropriateforces acting upon arms 64,65 for causing same to maintain contact withupright P are developed through tension cables 74,84 and spring 81.Thus, as shown in FIGS. 14 and 15, as arm 65 is swung rearwardly, apulling is effected upon cable 74 with a commensurate stressing ofspring 81;

said cable 74 following within the groove of sheave 73. Also, by reasonof the concurrent pulling of cable 84 about pulley 85, arm 64 is forcedto swing in a manner for assuring its blade will cut the relatedportions about upright P. As upright P moves relatively past apparatus Athe said arms will be returned to initial position through relief of thestress upon spring 81.

As above described, in conjunction with mowing apparatus A, theshiftability of mounting arm 60 with respect to beam 61 by reason ofswing arm 62,62 provides an emergency safety factor for protectingapparatus A in the event of undesired relative contact with anobstruction or upright to be trimmed.

With respect to mowing apparati A,A, as above described, it is to beapparent that the same could be mounted beneath a vehicle so that themounting arm, together with the blade carrying arms, would be presentedat a relatively more forward point on the vehicle for the desired usageby the operator. The function of course would be unchanged. Also theprovision of wheels 67 on apparatus A are merely demonstrative ofsuitable rotational members for closely following the terrain as well asaccording terminal support to the blade carrying arms.

Turning now to FIGS. 16 and 17, D generally indicates a further form ofmowing apparatus embodying the present invention and being of the typeadapted for disposition upon a manually directed vehicle as indicated atE; said latter incorporating a main frame supported by wheels 111,111and projecting from the normally rearward end thereof is an arm assembly112. Projecting forwardly on the opposite sides of main frame 110 aresupport arms 113,113 which at their forward ends are suitably secured toa transversely extending mounting bar 1 14 axially normal to thelongitudinal axis of vehicle E. Pivoted at their inner ends on mountingbar 114 at points mutually spaced apart but respectively proximate arms113,113 are arms 115,1 16 which normally project forwardly of mountingbar 114 in axially parallel relationship. Each of arms 115,116 at theirforward end carries a bracket 117 for mounting a wheel 118. Each arm115,116 rearwardly of their related wheel brackets 117 supports anupstanding hub 119 for journaling therein of a driven shaft 120 which attheir lower ends, below the respective arms 115,116, carry cutter blades(not shown). Rotatably mounted upon each hub 119 is a collar 121 rigidwith related cylindrical cutter guards 122, 122', which together withthe described related structure are in all respects identical with thecorresponding elements set forth in conjunction with apparatus Ahereinabove. I

The swingability of each arm 115,116 is controlled by a spring and cableassembly as indicated generally at 123 wherein an extension coil spring124 is adjustably connected to a bracket 125 fixed on mounting bar 114at the proximate end, and on the upper face, thereof. The opposite endof spring 124 is engaged to a cable 126 which extends in a directiontoward the centerline of vehicle E but immediately short thereof andinwardly of the arm, is directed about a sheave 127 rotatably mountedupon bar 114 for guiding said cable outwardly toward the associated armfor securement of its end upon a pin 128 fixed on such arm. Thus, byreason of the bias of springs 124, arms 115, 116 will be urged towardeach other so that cutter guards 122, 122 will normally be in mutualcontact (as shown in FIG.16).

The hub 119 on arm 116 is located slightly rearwardly of the related hubof arm 115 so as to present the respective cutter guard 112commensurately rearwardly of cutter guard 122 whereby the normal linecontact between said guards 122,122 will be in a rearward inner quadrantof cutter guard 122 as at d. In view of this relationship arm 116 may beshorter than arm 115.

In order to effect rotation of driven shafts 120 for blade operationpower may be supplied from a prime mover p carried on main frame 110 foroperating wheels 111,111 of said vehicle E. Thus, a takeoff 129 for saidprime mover p mounts a pulley 130 about which is trained the normallyrearward end of a drive belt 131, said latter extending forwardly fordisposition about a driven pulley 132, fixed on the end of a shaft 133of a gear box 134. Extending upwardly from gear box 134 is a drive shaft135 which mounts a two-groove sheave 136 for accommodating flexiblebelts 137,138 which at their opposite ends are respectively trainedabout pulleys 139,140 fixed upon the upper ends of hinge pins (notshown) by-which arms'115,1 16 are connected to mounting bar 114. Pulleys139, 140 are in turn operatively engaged to respective driven shafts 120by means of motion transmitting belts 141,142 suitably trained at theiropposite ends about pulleys 143,143 carried on the upper end of eachdriven shaft 120.

It will thus be seen that mowing apparatus D will operate in the samemanner as apparati A,A' above described with the distinction thatvehicle E is adapted for manual direction, although the same may bepowered for travel. Thus, the present invention is useful with the typeof mowing equipment handled by the average home owner and will assure ofappropriate trimming about trees, light post, and the like. Vehicle E isillustrated as merely exemplary of a hand guided unit since it is quiteapparent that apparatus D could be easily mounted upon like units ofvarying construction. In usage the operator will direct mowing apparatusD toward the particular upright to be trimmed (not shown) causing sameto move relatively between said guards 122,122and therepast towardmounting bar 114. The user will then necessarily have to pull vehicle Erearwardly for withdrawing the particular upright, as it were, from thespace adjacent bar 114. However, it is to be understood that thetrimming action entirely about the circumference of the particularupright is achieved during the forward movement; with the rearwardmovement being solely for disengaging purposes.

Having thus described my invention, what I desire and claim to obtainLetters Patent for is:

1. A mowing apparatus comprising means mountable upon a vehicle, firstand second arms swingably disposed at their normally rearward ends uponsaid mounting means, rotary blades provided at the outer end of each ofsaid arms, means supporting said blades upon each of said arms forrotation about an axis normal to the longitudinal axis of the relatedarm, means for effecting rotationof said blades, a guard carried uponeach arm surroundingly of the related blades, a first fluid assemblyoperatively engaged to said first arm, a second fluid assembly engagedto said second arm, a source of fluid connected to said first and secondfluid assemblies, said second fluid assembly being of relatively greatercapacity than said first fluid assembly for urging said second armtoward said first arm.

2. A mowing apparatus as defined in claim 1 and further characterized bysaid mounting means comprising a boom member, means swingably mountingsaid boom member upon said vehicle for rendering said boom memberaxially shiftable and yieldable means for urging said boom member intonormal operative position but allowing same to yield under appliedstress.

3. A mowing apparatus as defined in claim 1 and further characterized bysaid means mountable upon said vehicle being a boom, said first andsecond arm being swingably disposed in one end portion of said boom,said second arm being located laterally outwardly of said first arm,said first fluid assembly comprising a cylinder, means pivotallymounting one end of said first fluid assembly cylinder upon said boom, apiston provided within said last mentioned cylinder and having itsnormally outer end pivotally engaged to said first arm proximate itsengagement to said boom, said second fluid assembly having a cylinder,means supporting said second fluid assembly cylinder from said boom onthe opposite side thereof than said first fluid assembly, said secondfluid assembly cylinder having a piston, means engaging the outer end ofsaid last mentioned piston to said second arm, the stroke of said pistonof said second fluid assembly being longer than the stroke of saidpiston of said first fluid assembly.

4. A mowing apparatus as defined in claim 3 and further characterized bysaid boom being swingably mounted, and yieldable means urging saidboomfor presenting said first and second arms laterally outwardly ofsaid vehicle and yet permitting of yielding of said boom together withsaid arms under applied stress.

5. A mowing apparatus comprising means mountable upon a vehicle, firstand second arms swingably disposed at their normally rearward ends uponsaid mounting means, rotary blades provided at the outer end ofeach ofsaid arms, means supporting said blades upon each of said arms forrotation about an axis normal to the longitudinal axis of the relatedarm, means for effecting rotation of said blades, a spring member havingouter and inner ends, said outer end of said spring member beinganchored to said mounting means, and movable means connected to theinner end of said spring member and engaged to said first and secondarms, said movable means comprising a first cable secured at one end tosaid first arm, a second cable secured at one end to said second arm,and pivotally mounted means interconnecting said spring member and saidfirst and second cables.

6. A mowing apparatus as defined in claim 5 and further characterized bysaid movable means comprising a link pivotally engaged upon saidmountable means, and having a normally rearward and normally forwardend, said spring inner end being engaged to said link rearward end, abracket pivotally mounted on the forward end of said link, a first cableconnecting said bracket and said second arm, a second cable connectingsaid bracket and said first arm, and directing means provided on saidsecond arm for training thereabout of said second cable.

7. A mowing apparatus comprising means mountable upon a vehicle, firstand second arms swingably disposed at their normally rearward ends uponsaid mounting means, rotary blades provided at the outer end of each ofsaid arms, means supporting said blades upon each of said arms forrotation about an axis normal to the longitudinal axis of the relatedarm, means for effecting rotation of said blades, a guard carried uponeach arm surroundingly of the related blades, said arms being disposedin mutually spaced relationship upon said mounting means, first andsecond springs fixed at one of their ends upon said mounting means,

1. A mowing apparatus comprising means mountable upon a vehicle, firstand second arms swingably disposed at their normally rearward ends uponsaid mounting means, rotary blades provided at the outer end of each ofsaid arms, means supporting said blades upon each of said arms forrotation about an axis normal to the longitudinal axis of the relatedarm, means for effecting rotation of said blades, a guard carried uponeach arm surroundingly of the related blades, a first fluid assemblyoperatively engaged to said first arm, a second fluid assembly engagedto said second arm, a source of fluid connected to said first and secondfluid assemblies, said second fluid assembly being of relatively greatercapacity than said first fluid assembly for urging said second armtoward said first arm.
 1. A mowing apparatus comprising means mountableupon a vehicle, first and second arms swingably disposed at theirnormally rearward ends upon said mounting means, rotary blades providedat the outer end of each of said arms, means supporting said blades uponeach of said arms for rotation about an axis normal to the longitudinalaxis of the related arm, means for effecting rotation of said blades, aguard carried upon each arm surroundingly of the related blades, a firstfluid assembly operatively engaged to said first arm, a second fluidassembly engaged to said second arm, a source of fluid connected to saidfirst and second fluid assemblies, said second fluid assembly being ofrelatively greater capacity than said first fluid assembly for urgingsaid second arm toward said first arm.
 2. A mowing apparatus as definedin claim 1 and further characterized by said mounting means comprising aboom member, means swingably mounting said boom member upon said vehiclefor rendering said boOm member axially shiftable and yieldable means forurging said boom member into normal operative position but allowing sameto yield under applied stress.
 3. A mowing apparatus as defined in claim1 and further characterized by said means mountable upon said vehiclebeing a boom, said first and second arm being swingably disposed in oneend portion of said boom, said second arm being located laterallyoutwardly of said first arm, said first fluid assembly comprising acylinder, means pivotally mounting one end of said first fluid assemblycylinder upon said boom, a piston provided within said last mentionedcylinder and having its normally outer end pivotally engaged to saidfirst arm proximate its engagement to said boom, said second fluidassembly having a cylinder, means supporting said second fluid assemblycylinder from said boom on the opposite side thereof than said firstfluid assembly, said second fluid assembly cylinder having a piston,means engaging the outer end of said last mentioned piston to saidsecond arm, the stroke of said piston of said second fluid assemblybeing longer than the stroke of said piston of said first fluidassembly.
 4. A mowing apparatus as defined in claim 3 and furthercharacterized by said boom being swingably mounted, and yieldable meansurging said boom for presenting said first and second arms laterallyoutwardly of said vehicle and yet permitting of yielding of said boomtogether with said arms under applied stress.
 5. A mowing apparatuscomprising means mountable upon a vehicle, first and second armsswingably disposed at their normally rearward ends upon said mountingmeans, rotary blades provided at the outer end of each of said arms,means supporting said blades upon each of said arms for rotation aboutan axis normal to the longitudinal axis of the related arm, means foreffecting rotation of said blades, a spring member having outer andinner ends, said outer end of said spring member being anchored to saidmounting means, and movable means connected to the inner end of saidspring member and engaged to said first and second arms, said movablemeans comprising a first cable secured at one end to said first arm, asecond cable secured at one end to said second arm, and pivotallymounted means interconnecting said spring member and said first andsecond cables.
 6. A mowing apparatus as defined in claim 5 and furthercharacterized by said movable means comprising a link pivotally engagedupon said mountable means, and having a normally rearward and normallyforward end, said spring inner end being engaged to said link rearwardend, a bracket pivotally mounted on the forward end of said link, afirst cable connecting said bracket and said second arm, a second cableconnecting said bracket and said first arm, and directing means providedon said second arm for training thereabout of said second cable.
 7. Amowing apparatus comprising means mountable upon a vehicle, first andsecond arms swingably disposed at their normally rearward ends upon saidmounting means, rotary blades provided at the outer end of each of saidarms, means supporting said blades upon each of said arms for rotationabout an axis normal to the longitudinal axis of the related arm, meansfor effecting rotation of said blades, a guard carried upon each armsurroundingly of the related blades, said arms being disposed inmutually spaced relationship upon said mounting means, first and secondsprings fixed at one of their ends upon said mounting means,respectively, proximate said first and second arms and cablesinterconnecting the other ends of said first and second springs withsaid first and second arms, respectively.